Politics & Government

Bitter Antifreeze to Protect Pets

A new law that took effect this year requires a bitter additive in antifreeze to make it less attractive to animals.

A new state law that took effect Jan. 1 is meant to protect animals and children from a sweet death.

H. 4285, signed into law by Gov. Deval Patrick last summer, requires a bitter flavor agent to be added to all antifreeze to prevent animals and children from ingesting it. According to the Humane Society, 90,000 animals are poisoned each year by ingesting antifreeze. Antifreeze -- ethylene glycol -- has a sweet taste that attracts animals, and sometimes children, to drink it.

“This law will help protect our children, pets, and wildlife from the harmful effects of toxic chemicals,” Patrick said after signing the bill. “It's a common-sense public safety and public health measure.”

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The new law mandates that antifreeze manufacturers add denatonium benzoate to all antifreeze sold in Massachusetts. Denatonium benzonate is a foul, bitter-tasting chemical, and the law aims at using it to eliminate the sweet allure of antifreeze and thus deterring ingestion by those who don’t know any better.

The Signs

Dr. Nako Shinohara of  said that antifreeze poisoning is all too common in this area.

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"Unfortunately, we do see pets with antifreeze poisoning," Shinohara said. "Some pets come to the hospital with a known history of exposure; whereas, in some cases, we suspect poisoning due to clinical signs."

Because antifreeze is rapidly absorbed in the stomach, clinical signs of antifreeze poisoning can be seen within the first few hours and include:

  • Vomiting
  • Lethargy
  • Wobbly gait
  • Weakness
  • Increased Thirst
  • Increased urination

By about 12 hours, dogs and cats can develop signs of acute kidney failure, severe depression, coma and seizures.

Doctors use a blood test to measure how much antifreeze has been injested. It doesn't take a lot to do damage -- just 1.5 teaspoons can be lethal to an average-sized cat.

Don't Wait

If you suspect your pet may have injested antifreeze, take him or her to a veterinary hospital immediately. Tests for the poison are less accurate after 12 hours.

"Antifreeze poisoning requires prompt attention and treatment," Shinohara said. "The prognosis depends on how quickly the animal is diagnosed and receives treatment. Prognosis can be 'good' with early, aggressive therapy. Unfortunately, the prognosis is poor if treatment is delayed."

Treatment must be aggressive. Dogs may be treated with a medicine called Fomepizole and cats are often treated with ethanol. Treatment is followed up with an extended stay in the hospital for close monitoring and supportive care.

Bitter is Better

"There is another form of antifreeze on the market worth mentioning; they are made from propylene glycol," Shinohara said. "They are considered 'safer,' but are not 'safe.' Propylene glycol is about three times less toxic in dogs than ethylene glycol antifreeze. Caution is still advised and dogs and cats should be prevented from ingesting any type of antifreeze."

The new state law seeks to prevent that by taking the sweet taste out of antifreeze and discouraging animals from ingesting it. Massachusetts is the 13th state in the nation to pass such a law.

"This law is fitting for a state that has such a long history of being at the forefront of passing laws to protect those who cannot speak for themselves,” said the MSPCA’s Director of Advocacy Kara Holmquist. “The MSPCA-Angell operates one of the world’s largest animal hospitals, Angell Animal Medical Center, and without question, we see the tragic consequences of ingesting these poisonous chemicals.”


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